"Twelfth Night” duke (6)
I believe the answer is:
orsino
'twelfth night duke' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for orsino that I've seen before include "A Shakespearean role" , "Shakespearean duke" , "Twelfth Night duke" , "A duke, European" , "one in Twelfth Night" .)